Question
How much should I charge to lay 1340 sq ft of sod and top soil?

Answer
You'll need to determine what your materials, labor, profit, and overhead costs are.  Does this include underground irrigation installation, too?  Also access to the site may be an issue.

Here in our area, sod runs about $0.30/sf (contractor's cost, delivered)  Topsoil costs $25/yard, delivered.  A 2-man crew will run you about $200/day
A standard contractor profit is 30 - 35%.  Overhead may include office equipment, rental equipment, utilities, fees, professional licenses, truck, tools, business cards, etc., divided any way you see fit (hours/days/weeks)  $?? It is different for each company and/or job.  If its just for the job, maybe a fee of $150 - $200?  This is a judgement call for you.

So, to recap my example numbers -

Sod Mat'ls @ $0.30 x 1,340 sf = $402
topsoil Mat'ls @ $25/yd x 4" x 1,340 sf = $425  (1 yard at 4" covers about 81 sf, or 17 yards)
labor @ 2 days x $200 = $400
overhead @ $200
DIRECT COST SUBTOTAL = $1,427
PROFIT @ 30% - 35% = $428 to $500
TOTAL = $1,850 to $1,930 (I rounded it to the nearest $10)   

You can also do it by a square foot cost (1,930 / 1,340 ) = $1.38 to $1.44/sf

It is a judgement call, as far as what the market will bear (1.50/sf or $2.50/sf?), what your area charges for materials, labor, IRRIGATION, or what your overhead is.  But my example is the "bare bones" of keeping you in business, so you can keep installing sod for years to come!!

Hope it helps ~M